Eye tracking basics
      Back to home
      1. Knowledge base
      2. Hiru
      3. Eye tracking basics

      Can I use Hiru with certain eye conditions?

      With eye tracking, some special cases can arise depending on the user's age and eye conditions. Here are some tips to personalize the calibration and eye tracking experience!

      1. Personalize the calibration for the user: everything from colors, to speed to calibration points can be customized in most eye gaze software. In many eye tracking programs, you can even upload a personalized image for the calibration.
      2. Invisible calibration, Hiru App Balloon game and the Hiru’s calibration button can also be configured to provide a quick, one point calibration to get a user back on track when a new calibration is needed! The fewer the calibration points, the quicker it’ll be to get started learning, you can always build more precision in calibration as the user develops.

      Nystagmus

      Often eye gaze users who have nystagmus, can have difficulty calibrating, or controlling the pointer after calibration due to unintentional eye movements. To reduce this difficulty:

      • Decrease the dwell time:  Settings > Accessibility > Touch > Assistive Touch > Dwell time
      • Increase the smoothing: iPad  Settings > Accessibility > Touch > Assistive Touch > Device > Hiru > Smoothing
      • Increase the movement tolerance: Go to Settings > Accessibility > Touch > Assistive Touch
      • Check the positioning is good before starting the calibration. Take some time before the calibration on the positioning screen to check the eye detection (green dots) in all areas of the screen.  Have the user look around different areas of the screen with the positioning window open, and confirm that the green dots are present at all times, without flickering. If they start to flicker at any time when they look around the screen, try changing the position before starting a calibration. This will help avoid issues after the calibration.
        positioning hiru app         Keila eyes (1)

      Involuntary Head or Eye movements

      • Use a step by step calibration, available in most AAC software, to have more control over the moment when the camera captures the calibration information.
      • Wait till the user is positioned and gazing correctly, and trigger the calibration at that moment. Once the calibration is finished, you can also increase the smoothing level so that the mouse does not react so much to the involuntary movements.
      • If needed, Hiru can be programed to track only one eye. For users with eye conditions such as amblyopia, tracking only the user’s dominant eye can provide a more convenient and smooth eye tracking experience. Check Eye control mode in Hiru app for more.

      Amblyopia

      • Start with a good positioning.  This ensures good detection of the eyes, as well as helps identify if one eye has better detection by the eye tracker.
      • Calibrate, and check the calibration results. In Hiru App, check the results of each eye (Right, Left, Both).  If one eye has significantly better calibration results (ie. more points in green, fewer in red or yellow), go to Hiru app Settings, and select the stronger eye for the eye control mode.